There are apparatus' for reducing nitrogen oxides (NOx) from exhaust gases, but these apparatus' have normally been limited to the use of water injection systems for reducing NOx emission from the exhaust gases of combustion engines. Water injection systems in reciprocating engines have been used for increasing power and internal cooling, but not directly for reducing the formation of NOx.
Exhaust gas recirculation (EGR) has been used as a NOx reduction technique in reciprocating engines, but its use has been limited in diesel engines which are turbocharged and aftercooled, because normal engine aftercoolers are typically small finned core heat exchangers. The small air spaces in these heat exchangers are quickly fouled by soot which all diesel engines emit, even if only for startup. Accordingly, there is a need for an aftercooler apparatus that would solve the traditional aftercooler fouling problem seen with EGR systems while also cooling the intake air and reducing the formation of NOx emission levels.
Further, the presently used NOx reducing devices remove gaseous or particulate matter from the exhaust stream of an engine or apparatus through the use of chemical reagents, activated carbon filter elements or exhaust gas conditioners. There is a need for a NOx reducing apparatus that reduces the formation of NOx in the engine by treating the intake air to the engine, thereby also affecting the combustion process and eliminating the need to remove the sediment formation from NOx reducing after treatment type devices due to the concentration of soot or other such contaminants.
In order to overcome the above-mentioned defects in the previously known methods and apparatus' for reducing the NOx emissions from turbocharged engines, there is a need for an apparatus for reducing NOx emissions from turbocharged engines that acts on the intake air of the engine, not the exhaust gases, and that reduces the formation of NOx rather than removing it from the exhaust stream of the engine. There is also a need for an apparatus for reducing NOx emissions from turbocharged engines that does not require the removal of concentrated pollutants from the treatment device and which allows for the removal of traditional engine aftercooler devices thereby reducing air flow restriction and increasing fuel economy. There is also a need for an apparatus for reducing NOx emissions that uses water as a coolant without requiring the cooling water to be treated for the removal of dissolved solids in the water prior to using the water as a coolant. The apparatus of the present invention meeting these requirements is described in more detail below.